Last update:
06-Feb-2008

OBJECTIVE The aim of this study was to investigate the reliability and validity of the Greek version of the Kidney Disease Quality of Life Short Form (KDQOL-SF™).

METHOD The instrument was self-administered to a homogenous group of 933 end-stage renal disease patients in 25 dialysis units throughout Greece, and the overall response rate was 68.8%. The 19 scales of the instrument were tested for item internal consistency, item discriminant validity and scale reliability. Parametric tests were performed to ascertain the statistical significance of the observed differences in scale scores.

RESULTS The scales were generally reliable, with Cronbach's alpha exceeding the recommended minimum value of 0.70. Tests of item internal consistency demonstrated correlation between items and their hypothesized scales exceeding the 0.40 standard in 97.4% of cases. Item discriminant validity tests demonstrated 100% scaling success for seven out of eight generic and five out of eight disease-targeted scales. Validity was supported by the confirmation of hypothesized correlations of scales with the overall health-rating item included in the instrument, and with sociodemographic and self-reported health variables. Multiple stepwise linear regression analysis demonstrated that all disease-targeted scales were significant predictors of SF-36 general health scales, and the explained variance ranged from 36% to 57%.

CONCLUSIONS This first-time administration of the Greek version of the KDQOL-SF™ to a Greek dialysis population produced good results on both the generic and the disease targeted scales, indicating high validity and reliability. These findings enhance the confidence in administering the Greek KDQOL-SF™ in studies addressing health-related quality of life of dialysis patients.

Key words: Dialysis, Greece, KDQOL-SF™, Quality of life, Reliability, SF-36, Validity.